Are You Following The Ottawa Ankle Rules?

Submitted by Doug Richie Jr.... on Thu, 01/13/2011 - 08:50

Doug Richie Jr. DPM FACFAS

Last year, I was appointed to a panel to write a position statement for the National Athletic Trainers Association on the evaluation and treatment of the acute ankle sprain in the athlete. Part of my literature review has covered the Ottawa Ankle Rules (OARs) to determine their accuracy and reliability to rule out a fracture of the ankle after acute injury. It occurred to me that these clinical guidelines are not well known among podiatric physicians and a review of this subject may be beneficial.

It has been estimated that 80 to 98 percent of patients presenting to an emergency room who have suffered an ankle or mid-foot injury will undergo diagnostic X-ray evaluation.1 However, studies have shown that only 15 percent of all patients with such injuries will actually have a fracture.1,2 Routine orders for X-rays, which end up being negative on 85 percent of patients, cause unnecessary exposure to radiation, increased wait times in the emergency room and increased healthcare costs.

This led to the development of the Ottawa Ankle Rules, which were published by Stiell and colleagues in 1992.3 These rules recommend radiography after ankle injury if the patient demonstrates any of the following:

• age over 55;
• unable to bear weight for four steps either immediately after the injury or in the emergency room;
• palpable tenderness along the posterior edge of the distal 6 cm of the medial malleolus or lateral malleolus; or
• palpable tenderness at the tip of either the medial or lateral malleolus. (Note: Tenderness at the anterior margin of either malleolus would not justify use of an X-ray.)

In addition, foot radiographs are indicated when there is palpable tenderness at the base of the fifth metatarsal or at the navicular. You do not have to order radiographs after foot or ankle trauma if you follow the Ottawa Ankle Rules.

Since 1992, various researchers have studied the Ottawa Ankle Rules for accuracy and benefit. In a systematic review, Bachman and co-workers evaluated 27 published studies of the Ottawa Ankle Rules.4 Out of a total of 15,581 patients studied, the Ottawa Ankle Rules missed a fracture in only 47 patients (0.3 percent). Another meta-analysis of application of the Ottawa Ankle Rules in children (age 5 to 18) showed only 10 fractures missed in 3,130 patients.5 This is a missed fracture rate of 1.2 percent.

Overall, studies have shown that the Ottawa Ankle Rules will have 96 to 99 percent sensitivity, meaning that a negative test finding is a reasonable indicator that no fracture is present.6 Reviews of institutions that have implemented the Ottawa Ankle Rules have shown that there can be a reduction of 19 to 38 percent of radiography costs per year, resulting in a national cost savings of $90 million.6,7 The studies published over the past 20 years reporting accuracy of the Ottawa Ankle Rules have reflected an opinion from many medical disciplines that all clinicians should be following these guidelines in an attempt to reduce healthcare costs and eliminate needless exposure to radiation.4-6

Acute Ankle Injuries: When Should You Order X-Rays?

What about your own protocols for ordering X-rays for patients who have suffered an acute ankle or foot injury? Do you routinely order these studies or do you have examination criteria? I have been aware of the principles of the Ottawa Ankle Rules for over 20 years but am still afraid to apply them with 100 percent confidence in clinical practice.

My main fear is the possibility, although remote, is that even if you follow the Ottawa Ankle Rules, you may still fail to diagnose a fracture, which could lead to litigation. Unlike in Canada, where the Ottawa Ankle Rules were developed to reduce costs in their national healthcare system, chances of litigation for failure to diagnose are much greater here in the United States. Furthermore, the vast majority of my patients who present after an acute injury almost always demand an X-ray as part of their evaluation. This seems to be even more prevalent among anxious parents who bring their children into the office after an ankle injury.

In the end, I am certain that I will never be disciplined or sued for not following the Ottawa Ankle Rules and ordering X-rays even after not meeting the criteria. However, I am always fearful of the possibility that my failure to diagnose could lead to negative consequences. I am not confident that an expert witness will stand up on my behalf and show a jury that the medical literature backed me up for following the Ottawa Ankle Rules. Instead, the prevailing standard of care in my community will be the benchmark upon which I am judged.

In this case, most of my orthopedic and podiatric colleagues do not follow the Ottawa Ankle Rules. Do you?